Hydrothermal alteration and fluid inclusion geochemistry of auriferous deformation zones and vein systems, S.W. Michipicoten greenstone belt, Ontario.

Three stages of hydrothermal alteration have been identified at Wawa: (1) an early, pre- to syn-deformation alteration, represented by quartz-chlorite-Fe-dolomite-muscovite schists and chlorite-Fe-dolomite $\pm$ biotite schists (developed in felsic and mafic protoliths, respectively); (2) fenitization (biotite and riebeckite alteration) related to carbonatite-lamprophyre intrusives; and (3) late, fracture-related ankeritic and nematitic alteration. Events 1 and 3 are related to vein sets 1 and 3, respectively. Three generations of fluids have been recognized from fluid inclusion studies. The first fluid is an immiscible mixture of (1) high-salinity (18-23 wt. % NaCl), aqueous fluids, (2) low-salinity (4 to 7 wt. % NaCl), aqueous-carbonic fluids (XCO$\sb2\leq$ 20), and (3) CO$\sb2$-CH$\sb4$-N$\sb2$ fluids. This fluid is restricted to vein set 1 in the Surluga Mine and may have caused the early alteration in the Jubilee shear zone. The second fluid is a low- to moderate-salinity (5 to 16 Wt. % NaCl), aqueous fluid which may contain up to 10 mole % CO$\sb2$. The third fluid is a low-salinity (2 to 10 equiv. Wt. % NaCl) aqueous-carbonic fluid with significant amounts of CO$\sb2$ (XCO$\sb2$ = 0.23-0.35). (Abstract shortened by UMI.)Dept. of Geology and Geological Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1992 .B383. Source: Masters Abstracts International, Volume: 31-03, page: 1171. Supervisor: Iain M. Samson. Thesis (M.Sc.)--University of Windsor (Canada), 1992